Does anyone use a tug tow hook that releases automatically whenglider kites?

"Dan Marotta" wrote:

I just had a flash (brain fart) of an automatic release system. You
mechanical guys could probably make something like this work. Please bear
with me...

How about simply inverting a Schweizer release and mounting it on a sturdy
hinge. Then, in addition to the normal release rope, which the tuggie
should be able to release in any attutude, add a second release cable fixed
at the under side of the release, and forward of the hinge, such that, if
the hinge is rotated upward (as in kiting) the fixed cable draws tight and
releases the rope? The length of the fixed cable could be set to open the
release at a preset angle.

Seems simple enough. Please show me the error of my ways.

"kirk.stant" wrote in message
...
On Friday, February 21, 2014 11:41:20 AM UTC-6, Steve Leonard wrote:

Kirk, I don't think we want to consider a bridle from the tips. This
would require HUGE spar changes, as you could easily impart 500 lbs aft
force at both wing tips. This will pretty likely fold the wings aft and
make for a very high speed, although only vertical and down capable, tug.
Maybe the missle you were hoping to use? :-)

I know that - I was really just throwing out some hare-brained ideas to see
what would stick.

My solution is a lot simpler:

1. Near term: Replace ALL Schweizer tow hooks on tow planes with Tost hooks
(so you can at least release if you get upset high enough), then provide
very specific training to ALL glider pilots on the cause an effect of a tug
upset, to include a demo ride in a towplane at the receiving end. And treat
all aerotows of gliders with CG hooks as potential kiting accidents and
brief accordingly.

2. Long term: some sort of sensor controlled automatic release on tug to
eliminate problem, assuming our respective government aviation agencies will
agree to their installation. Make it mandatory so the numbers are high
enough to drop the price down to something affordable. And remember, it has
to not only apply to fixed tow hooks, but also to retractable tow ropes (now
how do you measure the forces?).

I still prefer the Bearcat towplane option. Kite away!

Kirk
66

We had a Schweizer tow hook on one of our tugs years ago, and it made
me suspicious about its performance under load. I decided to test it
by fixing the end of the tow rope round a tree and setting the tug on
full throttle. It was absolutley impossible to release at the tug end,
no matter how hard I pulled on the release cable.

We don't use them any more.